Many people prefer to develop their own photographic films in personal darkrooms rather than utilizing the services of commercial film developing houses. The developing equipment employed by hobbyists and other small-scale film developers is typically rather crude, generally consisting of a series of shallow pans or trays, and film holders or tongs for manipulating the film through the various liquid chemicals and rinses involved in its development. Such equipment must generally be manipulated under conditions of complete darkness and is clumsy to use under those conditions. In addition, the temperature of the developing chemicals and rinses plays an important part in the final quality of the developed film, and obtaining and maintaining the desired temperatures in the trays is difficult.
It is also typical for a hobbyist darkroom to be located in a closet, bathroom, storeroom, or some other room having a primary use other than as a darkroom. This means that between uses, the developing paraphernalia must be stored, and the commonly used trays, etc., are no more convenient to store than kitchen utensils, which they closely resemble.
Large-scale film developers have available to them special equipment for facilitating the development of film, such as that shown in U.S. Pat. Nos. 2,892,394; 2,925,767; 3,349,688; 3,470,810 and 3,890,629; but such equipment is generally too eleborate and expensive to be of interest or utility to photographic hobbyists.